Equilibrium between titania slags and metallic iron

摘要

The equilibrium between titania slags and liquid iron was studied in an induction furnace with a multiple segmented water-cooled copper crucible. The slags were either pure Fe-Ti-O melts or melts with addition of about 5 percent of either SiO_2, MgO or CaO, and the Ti_2O_3/FeO ratio of the slags was varied by addition of either metallic Ti or Fe_2O_3. The composition of the slag in equilibrium with liquid iron was found to follow an arched curve in the FeTiO_3-TiO_2-Ti_2O_3 ternary diagram, and with its apex slightly above the composition of the FeTi_2O_5-Ti_3O_5 solid solution line (the M_3O_5 phase). The melting temperature in the Fe-Ti-O system was studied, and showed a eutectic groove between the M_3O_5 phase and rutile or Magneli phases (Ti_nO_(2n-x))-Addition of about 5 percent of respectively SiO_2, MgO or CaO showed that these lowered the eutectic temperature and shifted the composition of the slag in equilibrium with iron closer to the M_3O_5 line. SiO_2 formed a separate silicate glass phase with small amounts of TiO_2 and FeO. MgO went into solid solution in the M_3O_5 phase where it substituted for FeO. CaO solidified mainly as perovskite, CaTiO_3, whereas small amounts went into solid solution in a Magneli phase.